Performance Based Design:
The Rational Method to Design for Hazards
Ph.D., PE, LEED AP BD+C -
Associate Principal, Thornton Tomasetti
As structural engineers, we rely on guidance and instructions provided in building codes to design for structures that properly account for different hazards. The prescriptive design methods provided in codes typically define the exact characterization of the hazards for which we design, how to analyze the effects on the structure, and how to design the structure to sustain the effects of the hazard.
Performance based design (PBD) is an alternative to prescriptive design, allowing for a more rational design. PBD properly accounts for the hazard specific to a structure, considers the performance appropriate for the structure (serviceability, life safety, economic impact, post-hazard performance, etc.), and explores the most rational ways to achieve the target performance. Being a rational design method, PBD allows for achieving better performance at the same cost, or lower cost for the same performance, and provides additional confidence and knowledge regarding the expected behavior of a structure. This presentation will briefly discuss the what, why, and how of performance based design, with a discussion involving the more mature field of seismic performance based design, as well as the developing fields of fire, wind, and flood performance based design.
Common Modeling Errors
Alex Bonnar, PE - Senior Structural Analyst, McNamara Salvia
The presentation will cover a broad range of modeling errors, from analysis models that don’t run to models seem to behave themselves but need to be checked for undetected mistakes. Sources of modeling error are divided into typographical, object geometry, object assignment, software analysis and design assumptions, and software bugs. Each category of error will be discussed through examples with suggested best practices to avoid them and detection strategies. Examples come from building design using RAM Structural System and ETABS, but the lessons will be applicable to engineering analysis packages in general.
Static Soil-Structure Interaction of
Buried Pipes, Culverts and Buried Bridges
Mark Webb, Ph.D., M.S.C.E
Staff Consultant | Simpson Gumpertz & Heger
The presentation will focus on the fundamental principles of pipe behavior, soil behavior, and soil-structure interaction relating to buried structures. Industry standards for the design of buried pipes, culverts and buried bridges will be discussed. Next, unusual or complex installations requiring finite element analysis (FEA) will be discussed. Modeling tips, techniques and pitfalls including topics such as: incremental construction, soil and structural material models, linear vs non-linear material behavior, 2D vs 3D FEA, interface elements, strip footings, and compaction effects will be discussed.
Richard Henige, Jr., PE, SE
Vice President | LeMessurier
See below for presenters' bios